1. Field of the Invention
The present invention relates to a speed-changing transmission device for vehicles and, more particularly, to an improvement in a speed-changing transmission device for vehicles, of the type having a counter shaft adapted to be driven by an input shaft which in turn is driven by an engine, a transmission shaft for driving a wheel axle or the like, the counter shaft and the speed-changing shaft being connected to each other through a forward transmission gear system and also through a backward transmission gear system, and clutches disposed in respective transmission paths and adapted to be selectively used to effect the changing of the speed.
2. Description of the Prior Art
In the conventional speed-changing transmission device for vehicles, when, for example, the pressure of the oil for operating the clutch for changing the speed is lowered due to the stop of the engine during parking, the clutch takes the "OFF" state to disconnect the driving wheel axle or the like from the engine. In this state, it is not possible to utilize the engine braking effect which is quite useful particularly when the vehicle is parked on a steep slope. In such a case, if the parking brake is operated insufficiently, the vehicle will naturally start dangerously. It is also to be pointed out that, in the event of an excessive discharge of the battery, it is not possible to start the engine by pushing the vehicle manually, because the driving wheel axle is disconnected from the engine.